Summary Forces and Gravitational Fields Physics Notes and Practice Problems

Section 12 2 .




now we consider object at Earths surface

we know that Fg =
mg where
, g 9 81
=
.
m/s
2




·
in free fall :

Fnet Fg : =
EmMe
?
RE

Ug = GmME
RE2

thus , g :
GME
RE2
if G , ME , RE , 9 81 m/s
you plug in you get g = .




technically ,
we have


= GM -




R2
S




·
with direction directly toward location of M


we call the
gravitational field caused by mass M

this separates the source of fg massM& the object experiencing Fg mass m)
EX . same configuration as before

Find g at location of m
,

then find Eg on m
,

Emma
mi Fiz m2
M, 41 g =
⑳ ⑧
McCullough
=
Gm
667x10
Mz Zing
Fi 9)
= :
is


Mz Ging =
32

My 5kg =




d 3m 1 48x10"ms2
=
⑧ ⑨ 92 = .




my M3
g2 1 48x10 "m/sa
-


= + .




g= 2
+
g3 +
g4

- 05x10" * 5 28x10 "y]m/s" (6 67410)
93
Gms
3 o
:

-
= .
=
. .

=




(32)"
Now ,
-
Fg on m
,
:




Fg GyC0s (-45)
"

g 93 m/s"
:




,l
= m
, ,
x =
= 1 57 x10
.




(4kg) (3 05 x10 "Y-5 28x10"y) m/s : 93 y gySin( 45) -1 57 x10-" m/s
-

= =
:
-
. .
.
,




-z (1 57 x 18" * 1 57x10-"G)
= .
-
.
mys
: